Issue link: https://viewer.e-digitaledition.com/i/692106
THE L ACK OF A MEDICATION TO TRE AT PRIMARY˜PROGRESSIVE MULTIPLE SCLEROSIS ¡PPMS¢ IS A SOURCE OF FRUSTR ATION FOR CLINICIANS AND PATIENTS. THE RESULTS OF A RECENT PHA SE 3 STUDY OF THE DRUG OCRELIZUMAB MAY BE CAUSE FOR HOPE. A N E S TIM ATED 400,000 Americans have MS, according to the Nationa l Multiple Sclerosis Society. Data show approximately 85 percent of individuals diagnosed with MS have relapsing-remit- ting MS (RRMS) at the time of diagnosis. Infl ammation is the hallmark of RRMS, as immune cells launch infl ammatory assaults against myelin and nerve fi bers. Individuals experience fl are-ups of symp- toms, followed by periods of remission. Approximately 15 percent of individu- als with MS are initially diagnosed with PPMS. Severa l factors ma ke PPMS more diœ cult to diagnose than RRMS, according to Claire Riley, MD, Assistant Professor of Neurology and Director of the Multiple Sclerosis Clinical Care and Research Center at Columbia University. These include fl uctuations in the disease course of PPMS that can mask progres- sion, as well as a bias among clinicians toward diagnosing RRMS, which is more treatable than PPMS. "One factor that makes [treating PPMS] challenging is that we've developed a lot of treatments that focus on infl ammatory activity," Dr. Riley says. "While there is some infl ammatory activity in people with PPMS, it seems like there are also degenerative changes going on — loss of [whole-brain] volume, loss of neurons. I think these degenerative diseases are much more challenging mechanistically to interfere with. Understanding why particular cells are vulnerable and helping them survive is ... a tough nut to crack." Researchers also face methodologi- cal hurdles. "St udies [focused on] PPMS have su- ered from their placebo group not pro- gressing fast enough to show a di- erence, A WAY Forward in Treating Primary-progressive Multiple Sclerosis? BY THOMAS CROCKER SPECIAL CLINICAL SECTION: NEUROLOGY 2 0